Last issue
2018 (vol. 28) - Number 1


I. Duleba, I. Karcz-Duleba:

A comparison of methods solving repeatable inverse kinematics for robot manipulators



A. Niederliński:

A new approach for modelling uncertainty in expert systems knowledge bases



T.T. Tuan, L.D. Tufa, M.I.A. Mutalib, N.M. Ramli :

Optimal operation of a process by integrating dynamic economic optimization and model predictive control formulated with empirical model



M. Kaleta:

Network winner determination problem



A. Kowalewski:

Extremal problems for parabolic systems with time-varying lags



T. Rybus, K. Seweryn, J.Z. S±siadek:

Application of predictive control for manipulator mounted on a satellite



T. Kaczorek:

Reachability and observability of positive discrete-time linear systems with integer positive and negative powers of the state Frobenius matrices



G. Grassi, A. Ouannas, V-T. Pham:

A general unified approach to chaos synchronization in~continuous-time systems (with or without equilibrium points) as well as in discrete-time systems



D. Pazderski:

A robust smooth controller for a unicycle-like robot




ACS Abstract:

2001 (Volume 11)
Number 1/2
1. Monitoring and control of a class of distributed parameter bioreactors with application of the substrate consumption rate
2. Optimal control for bilinear systems with delay on control
3. On an NP-hard sorting problem
4. Low gain adaptive stabilization of undamped second order systems
5. Observability of a generalized linear control system
6. Very fast algorithm for nonholonomic optimal path planning and replanning, generalities and details


Monitoring and control of a class of distributed parameter bioreactors with application of the substrate consumption rateDownload full PDF article
J.P.Babary
(Centre National de la Recherche Scientifique, France)
J.Czeczot, M.Metzger
(Silesian University of Technology, Poland)
M. Nihtilä
(University of Kuopio, Finland)

This paper deals with the idea of estimation of the substrate consumption rate at each point of the tube of the classical distributed parameter bioreactor and with its application to the monitoring and control of this system. It is shown how to approximate the profile of this parameter on the basis of the orthogonal collocation method and of the recursive least-squares procedure with adjustable forgetting factor. Then, it is suggested how to apply this profile for monitoring of the bioreactor work (calculation of the current mass flux of the substrate being reacted in the reactor tube and of the total mass of the substrate converted in the bioreactor during its activity). Finally, the linearizing adaptive control law is derived on the basis of the substrate consumption rate estimated at the outlet of the bioreactor. This controller allows the outlet substrate concentration to be kept at its desired value by manipulating the velocity of the flowing medium. The idea presented in this paper has been validated by means of the computer simulation and the results, proving its very good properties, complete the paper.

keywords: biotechnology, distributed parameter systems, monitoring, model-based adaptive control, recursive least-squares estimation.

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Optimal control for bilinear systems with delay on controlDownload full PDF article
A. Eljai
(Université de Perpignan, France)
J. Karrakchou
(Ecole Mohamadia d'Ingénieurs, Maroc)
M.Rachik, M.Lhous
(Faculté des Sciences Ben M'sik, Maroc)

The quadratic optimal control for bilinear distributed systems with delays in the control is considered. A semigroup model which involves no explicit delays in control is introduced. In the case of continuous delay, the control operator is bounded and the classical results can be applied. The case of general delays can be considered as a distributed system with boundary control. With the aid of a family of approximating systems, it is shown that the optimal control is obtained as a limit of sequence which is solution of classical control problems.

keywords: optimal control, bilinear systems, delayed systems.

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On an NP-hard sorting problemDownload full PDF article
K. Giaro
(Technical University of Gdańsk, Poland)

We show that the following problem: given a sequence of numbers; arrange these numbers into order using as few interchanges as possible cannot be solved in polynomial time, unless P=NP.

keywords: sorting problem, NP-hardness, flexible manufacturing systems.

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Low gain adaptive stabilization of undamped second order systemsDownload full PDF article
Toshihiro Kobayashi
(Kyushu Institute of Technology, Japan)

In this paper low-gain adaptive stabilization of undamped second order systems is considered in the case of collocated input and output operators. The systems have poles and zeros on the imaginary axis. In the case where velocity feedback is available, the adaptive stabilizer is constructed by an adaptive low-gain PD-controller (proportional plus derivative controller). In the case where only position feedback is available, the adaptive stabilizer is constructed by a low-gain adaptive P-controller for the augmented system which consists of the controlled system and a parallel compensator. Numerical examples are given to illustrate the effectiveness of the proposed cntrollers.

keywords: low-gain feedback, adaptive stabilization, undamped second order dynamical systems.

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Observability of a generalized linear control systemDownload full PDF article
Hubert Wysocki
(Naval Academy, Poland)

In this paper a definition of observability of a generalized linear differential control system in the terms of the Bittner Operational Calculus is introduced. Some observability criteria are also discussed.

keywords: observability, linear differential systems, observability criteria, Bittner Operational Calculus.

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Very fast algorithm for nonholonomic optimal path planning and replanning, generalities and detailsDownload full PDF article
Leszek Podsźdkowski
(Technical University of £ód¼, Poland)

This paper presents an original method for nonholonomic mobile robot path planning. The method is based on A* searching of a graph built in a configuration space. Very good heuristic approximation of the real cost of the path accelerates path searching significantly. Due to dynamic modifications of the graph, the path replanning procedure is much faster than Brute-Force replanner. The paper presents general assumptions of the method, detailed algorithms of important procedures (especially the path replanning procedure) and a new form of Configuration Space and Open List. The simulation and experimental tests on car-like robot as well as the comparisons of this method to the others are also included.

keywords: nonholonomic robots, dynamic path planning, graph searching.

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